A 65-year-old widowed Portuguese woman woke up one morning and felt no sense of ownership to her decades-old belongings, reports a new study published last week. While her unsettling experience granted her little in the way of a diagnosis (it only lasted three days), it did show psychiatrists the importance of ownership and material possessions as they relate to identity and self-expression.

"People express their self-identity through their belongings, a notion that psychologists and neuroscientists are lately finding empirical evidence to support," writes New York magazine's Melissa Dahl. In fact, there are entire regions of the brain devoted to a person's sense of ownership, as evidenced by a 2011 study on neuroimaging. The researchers noted that certain areas of participant's brains lit up when looking at their own possessions as opposed to someone else's. These areas just so happened to be linked to "self-referential encoding and memory," or identity formation and self-concept.

You'll likely notice this self-concept begin to take shape in your little ones, evidenced by their blanketed claim on everything as "mine!" According to Dahl, they are simply using possessions to inform their own sense of self—something that doesn't necessarily disappear with age. So next time somebody chides you for your endless shopping trips to IKEA, tell them that you're simply enriching your sense of self.

This story was originally published on July 19, 2016, and has been updated by Sacha Strebe.